Is there a builtin function for formatting time values?

I have to this to extract formated times from timestamps, but I
suspect there is something much better, even if it uses a stored
procedure. The lpad command to is also funny because I have to
concatenate it with an empty quote to convert the output to a string.

select lpad(extract(hour from calldate) || '', 2, '0') || ':' ||
lpad(extract(minute from calldate) || '', 2, '0') || ':' ||
lpad(extract(second from calldate) || '', 2, '0') from asterisk_cdr

There must be a formattted into to string function or a formatted time
function somewhere.

Are there any links to PostgreSQL stored procedure libraries?

/voipfc